[glom] FlowTableWithFields: Remove unused member variable.

[Murray Cumming <murrayc src gnome org>]

commit df59b8e3af4d49c20f85922e51ec0204505ef0ea
Author: Murray Cumming <murrayc murrayc com>
Date:   Sun Nov 6 20:59:23 2016 +0100

    FlowTableWithFields: Remove unused member variable.
    
    Found by clang++-3.9

 glom/mode_data/flowtablewithfields.cc |    2 --
 glom/mode_data/flowtablewithfields.h  |    3 ---
 2 files changed, 0 insertions(+), 5 deletions(-)
---
diff --git a/glom/mode_data/flowtablewithfields.cc b/glom/mode_data/flowtablewithfields.cc
index 61aa89c..9153138 100644
--- a/glom/mode_data/flowtablewithfields.cc
+++ b/glom/mode_data/flowtablewithfields.cc
@@ -35,7 +35,6 @@
 #include <glom/mode_data/box_data_list_related.h>
 #include <glom/mode_design/layout/dialog_choose_relationship.h>
 #include <glom/utils_ui.h> //For bold_message()).
-#include <libglom/data_structure/layout/layoutitem_placeholder.h>
 #include <glom/signal_reemitter.h>
 
 #include <glibmm/i18n.h>
@@ -53,7 +52,6 @@ FlowTableWithFields::Info::Info()
 
 FlowTableWithFields::FlowTableWithFields(const Glib::ustring& table_name)
 :
-  m_placeholder(nullptr),
   m_table_name(table_name),
   m_find_mode(false)
 {
diff --git a/glom/mode_data/flowtablewithfields.h b/glom/mode_data/flowtablewithfields.h
index 3aeb6b3..be165a5 100644
--- a/glom/mode_data/flowtablewithfields.h
+++ b/glom/mode_data/flowtablewithfields.h
@@ -31,7 +31,6 @@
 #include <libglom/data_structure/layout/layoutitem_calendarportal.h>
 #include <libglom/data_structure/layout/layoutitem_button.h>
 #include <libglom/data_structure/layout/layoutitem_text.h>
-#include <libglom/data_structure/layout/layoutitem_placeholder.h>
 #include <libglom/data_structure/field.h>
 #include <libglom/document/document.h>
 #include <glom/utility_widgets/layoutwidgetbase.h>
@@ -265,8 +264,6 @@ private:
   Box_Data_List_Related* create_related(const std::shared_ptr<LayoutItem_Portal>& portal, bool show_title = 
true);
   Box_Data_Calendar_Related* create_related_calendar(const std::shared_ptr<LayoutItem_CalendarPortal>& 
portal, bool show_title = true);
 
-  Gtk::Bin* m_placeholder;
-
   Glib::ustring m_table_name;
   bool m_find_mode;